JP2013125620A - Induction heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating apparatus which is strong against displacement of a transmission coil and a cooking container, and has high transmission efficiency.SOLUTION: A pot 123 is provided in close proximity of a transmission coil 1 so as to be coupled electromagnetically therewith. The transmission coil 1 is provided along a horizontal first surface so as to wind a winding around a predetermined region thereon. The induction heating apparatus includes a magnetic material 3 provided in close proximity of the transmission coil 1 so as to be coupled electromagnetically therewith at least over a region where the winding of the transmission coil 1 exists, between the first surface and a second surface facing the first surface in close proximity to the upper part thereof where the bottom face of the pot 123 is located. Self-inductance of the transmission coil 1 is increased by bringing the transmission coil 1 close to the magnetic material 3.

Description

  The present invention relates to an induction heating apparatus using inductive coupling between coils.

  In recent years, non-contact connector devices and non-contact connector systems using inductive coupling between coils to perform wireless charging in mobile electronic devices and EV devices such as mobile phones and electric vehicles, and electric power provided therewith Development of transmission devices and power transmission systems is in progress. As a non-contact power transmission system, for example, the inventions of Patent Documents 1 to 3 are known.

  The non-contact power feeding device of Patent Document 1 includes furniture provided with a primary coil for power to which power is supplied, and the magnetic flux generated by the primary coil for power in a state of being arranged at a predetermined arrangement position with respect to the furniture. It is characterized by comprising a cordless device provided with a secondary coil for electric power to be arranged and an informing means for informing a predetermined arrangement position of the cordless device with respect to furniture.

  The non-contact power transmission coil of Patent Document 2 includes a planar coil formed by spirally winding a linear conductor in substantially the same plane, and a liquid magnetic material solution in which magnetic particles are mixed in a binder solvent. And a magnetic layer formed by coating so as to cover one planar portion of the planar coil and the side portion of the planar coil.

  The wireless transmission system of Patent Document 3 includes a resonator for wireless power transmission, which includes a conductor that forms one or more loops and has a predetermined inductance, a predetermined capacitance, and a desired electrical parameter. And a capacitor network connected to the conductor. Wherein the capacitor network includes at least one capacitor of a first type having a first temperature profile as an electrical parameter and at least one capacitor of a second type having a second temperature profile as an electrical parameter. And have.

  The principle of such a non-contact power transmission system can be applied to an information transmission system including a non-contact connector device and an induction heating device such as an IH cooking device.

JP 2001-309579 A JP 2008-172873 A US Patent Application Publication No. 2010/0181845

  In order to achieve high transmission efficiency in a non-contact power transmission system, a transmission coil provided in a transmission-side power transmission device (for example, a charger) and a reception-side power transmission device (for example, a charger) are provided. It is necessary to accurately match the positions of the transmission coil and the reception coil so that the reception coil is electromagnetically strongly coupled.

  According to the inventions of Patent Documents 1 and 2, a high transmission efficiency can be realized if the positions of the opposed transmission coil and reception coil are accurately matched, but there is a problem that the transmission efficiency is lowered when the positions are shifted.

  In order to solve the decrease in transmission efficiency due to misalignment, in the invention of Patent Document 3, the matching circuit is dynamically changed. However, such a solution has a problem of complicated control.

  Similar problems exist not only in non-contact power transmission systems but also in information transmission systems including non-contact connector devices and induction heating devices.

  An object of the present invention is to provide an induction heating apparatus that solves the above-described problems and has a simple configuration but is resistant to displacement of the transmission coil and the reception coil and has high transmission efficiency.

According to the induction heating device according to the aspect of the present invention,
In an induction heating apparatus provided with an induction heating coil provided in close proximity so as to be electromagnetically coupled to a cooking vessel,
The induction heating coil winding is wound on a horizontal first surface;
The induction heating device is
At least the winding of the induction heating coil and the cooking vessel between the first surface and a second surface that is close to and opposes the upper side of the first surface and on which the bottom surface of the cooking vessel is located A magnetic body provided in proximity to the induction heating coil and the bottom surface of the cooking vessel over a region where the bottom surface of
The self-inductance of the induction heating coil is increased by bringing the magnetic body close to the induction heating coil, and the self-inductance of the cooking container is increased by bringing the bottom surface of the cooking container close to the magnetic body. And

  The induction heating device increases a self-inductance of each of the induction heating coil and the cooking container, thereby increasing a coupling coefficient between the induction heating coil and the cooking container from the induction heating coil to the cooking container. The frequency characteristic of the transmission efficiency is set to be lowered so that the characteristic changes from a bimodal and narrowband characteristic to a unimodal and broadband characteristic.

  In the induction heating device, the winding of the induction heating coil is wound in a single layer along the first surface.

  In the induction heating device, the windings of the induction heating coil are wound in multiple layers along the first surface, and the windings of each layer of the multilayer windings are connected in series with each other. And

  In the induction heating device, the windings of the induction heating coil are wound in multiple layers along the first surface, and the windings of each layer of the multilayer windings are connected in parallel to each other. And

In the induction heating apparatus,
The winding of the induction heating coil is formed as a conductor pattern on the dielectric substrate along the first surface,
The magnetic body is formed integrally with the induction heating coil and the dielectric substrate.

  According to the induction heating device of the present invention, the cooking container can be heated with a stable transmission efficiency even if a positional shift occurs between the induction heating coil and the cooking container, although the configuration is very simple.

1 is a perspective view showing a schematic configuration of a power transmission system according to a first embodiment of the present invention. It is sectional drawing in the A-A 'line of FIG. It is sectional drawing which shows schematic structure of the electric power transmission system of a comparative example. It is a circuit diagram which shows an example of the equivalent circuit of the electric power transmission system of FIG. It is the schematic which shows the frequency characteristic of the transmission efficiency when the coupling coefficient k between the transmission coil 1 and the reception coil 2 of FIG. 3 is changed. It is the schematic which shows the flow of the magnetic flux in the electric power transmission system of FIG. FIG. 4 is a schematic diagram showing the flow of magnetic flux when the distance d between the transmission coil 1 and the reception coil 2 is increased in the power transmission system of FIG. 3. FIG. 4 is a schematic diagram showing the flow of magnetic flux when the distance d between the transmission coil 1 and the reception coil 2 is increased and the magnetic body 6 is inserted in the power transmission system of FIG. 3. It is the schematic which shows the flow of the magnetic flux in the electric power transmission system of FIG. FIG. 2 is a schematic diagram showing the flow of magnetic flux when the positions of a transmission coil 1 and a reception coil 2 are shifted in the power transmission system of FIG. 1. 1 is a perspective view illustrating a schematic configuration of a power transmission system according to a first embodiment of the present invention. FIG. 12 is a top view of the power transmission system of FIG. 11. It is sectional drawing in the B-B 'line | wire of FIG. It is a circuit diagram which shows the equivalent circuit of the electric power transmission system of FIG. It is a figure explaining the position shift produced between the transmission coil 1 and the receiving coil 2 in the electric power transmission system of FIG. 12 is a graph showing frequency characteristics of transmission efficiency when the positional deviation between the transmission coil 1 and the reception coil 2 is changed in the power transmission system of FIG. 11 from which the magnetic body 3 is removed. 12 is a graph showing frequency characteristics of transmission efficiency when the positional deviation between the transmission coil 1 and the reception coil 2 is changed in the power transmission system of FIG. 11. It is a graph which shows the characteristic of the transmission efficiency with respect to position shift of the electric power transmission system of FIG. 12 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. 11. 12 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. 11 in which the thickness of the magnetic body 3 is reduced. 12 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. 11 in which the thickness of the magnetic body 3 is reduced. It is a top view which shows schematic structure of the electric power transmission system which concerns on 2nd Example of this invention. FIG. 23 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. 22 from which a cavity is removed. 24 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. It is sectional drawing which shows schematic structure of the electric power transmission system which concerns on the 3rd Example of this invention. It is a top view which shows the transmission coil 1 and the reception coil 2 of FIG. It is a graph which shows the frequency characteristic of the transmission efficiency of the electric power transmission system of FIG. 1 is a block diagram showing a schematic configuration of a power transmission system according to a first embodiment of the present invention. It is sectional drawing which shows the structure of the power transmission apparatus by the side of power transmission in the power transmission system of FIG. FIG. 26 is a cross-sectional view illustrating a configuration of a modified example of the power transmission device on the power transmission side and the power transmission device on the power reception side in the power transmission system of FIG. 25. It is a block diagram which shows schematic structure of the signal transmission system which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows schematic structure of the induction heating apparatus which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the induction heating apparatus of FIG. It is sectional drawing which shows the modification of the transmission coil 1 and the reception coil 2 of FIG. It is the schematic explaining how to wind the transmission coil 1 of FIG. It is the schematic explaining the modification of how to wind the transmission coil 1 of FIG. It is sectional drawing which shows the modification of the non-contact connector apparatus of the transmission side of FIG. 1, and a reception side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same component.

First embodiment.
FIG. 1 is a perspective view showing a schematic configuration of a power transmission system according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line AA ′ of FIG. The power transmission system according to the present embodiment includes a non-contact connector system using electromagnetic coupling between the transmission coil 1 and the reception coil 2. In FIG. 1 and others, for simplification of illustration, the power source, power transmission circuit, power reception circuit, and the like necessary for the power transmission system are omitted, and only the non-contact connector system is shown. Note that the non-contact connector system includes a transmission-side non-contact connector device including the transmission coil 1 and a reception-side non-contact connector device including the reception coil 2.

  In the power transmission system of FIG. 1, the non-contact connector system includes a transmission coil 1 and a reception coil 2 provided along a first surface and a second surface that face each other in proximity to each other. The transmission coil 1 has terminals P1a and P1b, and the reception coil 2 has terminals P2a and P2b. Transmitting coil 1 and receiving coil 2 are provided close to each other so as to be electromagnetically coupled to each other. Transmitting coil 1 is provided along the first surface so as to wind a winding around a predetermined region on the first surface. Similarly, the receiving coil 2 is provided along the second surface so as to wind a winding around a predetermined region on the second surface. The non-contact connector system is electromagnetically coupled to the transmission coil 1 and the reception coil 2 at least over a region where the windings of the transmission coil 1 and the reception coil 2 exist between the first surface and the second surface. Is provided with a magnetic body 3 having a predetermined relative magnetic permeability, which is provided in the vicinity of. The magnetic body 3 is, for example, ferrite. The self-inductance of the transmission coil 1 is increased by bringing the magnetic body 3 close to the transmission coil 1, and the self-inductance of the reception coil 2 is increased by bringing the magnetic body 3 close to the reception coil 2.

  In the power transmission system of this embodiment, the coupling coefficient between the transmission coil 1 and the reception coil 2 is increased from the transmission coil 1 to the reception coil 2 by increasing the respective self-inductances of the transmission coil 1 and the reception coil 2. The frequency characteristic of the transmission efficiency is set to be lowered so that the characteristic changes from a bimodal and narrowband characteristic to a unimodal and broadband characteristic.

  Hereinafter, the operation principle of the non-contact connector system of this embodiment will be described.

  FIG. 3 is a cross-sectional view illustrating a schematic configuration of a power transmission system of a comparative example. In the power transmission system of FIG. 3, the non-contact connector system is the same as the non-contact connector system of FIG. 1 except that the magnetic body 3 is not provided. The transmission coil 1 is provided in the housing 4 of the non-contact connector device on the transmission side, and the reception coil 2 is provided in the housing 5 of the non-contact connector device on the reception side. The transmission coil 1 and the reception coil 2 are separated by a distance d.

  In the power transmission system of FIG. 3, when a current flows through the transmission coil 1, an induced electromotive force is generated in the reception coil 2 due to an electromagnetic field around the transmission coil 1 formed by the current, and an induced current flows in the reception coil 2. . In other words, the transmission coil 1 and the reception coil 2 are electromagnetically coupled to each other. As an index for evaluating the degree of coupling, a coupling coefficient k of the following formula is used.

k = M / (√L1 × √L2) (0 ≦ | k | ≦ 1)

  Here, M represents a mutual inductance between the transmission coil 1 and the reception coil 2, L1 represents a self-inductance of the transmission coil 1, and L2 represents a self-inductance of the reception coil 2.

  FIG. 4 is a circuit diagram showing an example of an equivalent circuit of the power transmission system of FIG. Q is a signal source, z01 is a load impedance of the transmission circuit, z02 is a load impedance of the reception circuit and the load, R1 and R2 are resistors, and C1 and C2 are matching capacitors. When the power transmission system operates at the angular frequency ω, the parameter S21 representing the transmission efficiency can be expressed by the following equation using the self-inductances L1 and L2 and the mutual inductance M.

  Note that the equivalent circuit of FIG. 4 and the expression of the parameter S21 are merely examples, and the equivalent circuit and transmission efficiency of the power transmission system may be represented by any other appropriate model.

  When the transmission coil 1 and the reception coil 2 are electromagnetically strongly coupled, | k | ≈1, but as the distance d increases, the value of | k | decreases, and the transmission coil 1 and the reception coil When the coil 2 is not electromagnetically coupled, | k | = 0.

  FIG. 5 is a schematic diagram showing frequency characteristics of transmission efficiency when the coupling coefficient k between the transmission coil 1 and the reception coil 2 in FIG. 3 is changed. In FIG. 5, it is assumed that the Q value is constant. According to FIG. 5, it can be seen that the bandwidth of transmission efficiency changes according to the magnitude of the coupling coefficient k. Normally, when the electromagnetic coupling between the transmission coil 1 and the reception coil 2 is strong, the characteristics are bimodal and narrow band, and wide band operation cannot be realized. That is, in order to realize a broadband operation, it is necessary to reduce the coupling coefficient k under the condition where the transmission coil 1 and the reception coil 2 are close to each other. Since the coupling coefficient k is the ratio of the square root of the self-inductances L1 and L2 and the mutual inductance M, the coupling coefficient k can be lowered if the self-inductances L1 and L2 can be increased.

  6 to 8 are schematic views showing the flow of magnetic flux in the power transmission system of FIG. 6 to 8, the casings 4 and 5 in FIG. 3 are omitted, and only the transmission coil 1 and the reception coil 2 are shown. When the transmitting coil 1 and the receiving coil 2 are close to each other as shown in FIG. 6, when a current flows through the transmitting coil 1, magnetic fluxes M1a and M1b are formed so as to surround both the transmitting coil 1 and the receiving coil 2. The mutual inductance M increases and the coupling coefficient k increases. FIG. 7 is a schematic diagram showing the flow of magnetic flux when the distance d between the transmission coil 1 and the reception coil 2 is increased in the power transmission system of FIG. When the transmission coil 1 and the reception coil 2 are separated from each other as shown in FIG. 7, when a current flows through the transmission coil 1, a part of the magnetic flux M <b> 2 a among the magnetic fluxes formed around the transmission coil 1 and the reception coil 2. , M2b becomes a leakage magnetic flux, so that the mutual inductance M decreases and the coupling coefficient k decreases. FIG. 8 is a schematic diagram showing the flow of magnetic flux when the distance d between the transmission coil 1 and the reception coil 2 is increased and the magnetic body 6 is inserted in the power transmission system of FIG. When the transmission coil 1 and the reception coil 2 are separated from each other, the magnetic body 6 (iron, ferrite, etc.) is inserted into the central portion of the transmission coil 1 and the reception coil 2 as shown in FIG. The magnetic fluxes M2a and M2b can be changed to a magnetic flux M1b that passes through the inside of the magnetic body 6 and surrounds both the transmission coil 1 and the reception coil 2, and as a result, the mutual inductance M increases and the coupling coefficient k is increased. Get higher.

  As shown in FIG. 6, under the condition where the transmission coil 1 and the reception coil 2 are close to each other, as described above, the coupling coefficient k becomes high, so that it is not possible to realize a broadband operation. Therefore, it is necessary to increase the self-inductances L1 and L2 instead of controlling the flow of magnetic flux and reducing the mutual inductance M.

  FIG. 9 is a schematic diagram showing the flow of magnetic flux in the power transmission system of FIG. When a current flows through the transmission coil 1, a part of the magnetic flux M1 passes through the magnetic body 3 and surrounds both the transmission coil 1 and the reception coil 2, but the other part of the magnetic flux M2a is In the magnetic body 3, it passes only in the vicinity of the transmission coil 1, does not go to the reception coil 2, and is formed as a leakage magnetic flux surrounding only the transmission coil 1. By forming the leakage magnetic flux M2a, the self-inductance L1 of the transmission coil 1 increases. Similarly, when an induced current flows through the receiving coil 2, a leakage magnetic flux M2b surrounding only the receiving coil 2 is formed without passing toward the transmitting coil 1 only in the vicinity of the receiving coil 2 in the magnetic body 3. . By forming the leakage magnetic flux M2b, the self-inductance L2 of the receiving coil 2 increases. As described above, in the power transmission system of FIG. 1, the self-inductances L1 and L2 increase due to the provision of the magnetic body 3, and the coupling coefficient k becomes lower than in the case of FIG. can do.

  FIG. 10 is a schematic diagram showing the flow of magnetic flux when the positions of the transmission coil 1 and the reception coil 2 are shifted in the power transmission system of FIG. Also in this case, similarly to the case of FIG. 9, the leakage magnetic flux M2a surrounding only the transmission coil 1 and the leakage magnetic flux M2b surrounding only the reception coil 2 are formed. For this reason, as in the case of FIG. 9, the self-inductances L1 and L2 increase due to the provision of the magnetic body 3, and the coupling coefficient k becomes lower than that in the case of FIG. be able to.

  A preferred coupling coefficient k will be described with reference to FIG. As described above, when the electromagnetic coupling between the transmission coil 1 and the reception coil 2 is strong, it is a bimodal and narrow-band characteristic. However, when the coupling coefficient k is gradually decreased, the transmission efficiency is reduced between two peaks. , And the minimum value of the transmission efficiency between the two peaks gradually increases. When this frequency interval is substantially zero, in other words, when the difference between the two peaks of transmission efficiency and the local minimum between them is small (eg 5-10%), the bandwidth of the power transmission system is Become the maximum. The coupling coefficient k is determined so as to satisfy this condition, and the parameters of the power transmission system (thickness and relative permeability of the magnetic body 3, transmission coil 1 and reception coil are set so as to achieve the value of the coupling coefficient k. 2 turns, etc.) are determined.

  When the magnetic body 3 is provided between the transmission coil 1 and the reception coil 2 separated by a distance d, as will be described later with reference to FIG. 27, there is no magnetic body (“no magnetic body, d = 2. 6mm ", a dot-and-dash line plot) was bimodal and narrow band characteristics, but with a magnetic body (" with magnetic body, d = 2.6mm ", solid line plot), unimodal and broadband characteristics become. In the case of a power transmission system not having a magnetic body, the coupling coefficient k is high, so that bimodal characteristics are shown. However, in the case of the power transmission system of the present embodiment, the coupling coefficient k is reduced due to the effect of the magnetic body 3. Wide band operation can be realized. Further, according to FIG. 27, there is no magnetic body (“no magnetic body, d = 2.6 mm”, dot-dash line plot) and magnetic bodies (“with magnetic body, d = 2.6 mm”, solid line plot). When the magnetic body 3 is provided, the resonance frequency decreases from 250 kHz to 150 kHz due to the increase of the self-inductances L1 and L2. In other words, in the power transmission system of the present embodiment, the effect of miniaturization can be obtained by reducing the resonance frequency.

  Next, with reference to FIG. 11 to FIG. 18, resistance to displacement of the transmission coil 1 and the reception coil 2 of the power transmission system of the present embodiment will be described.

  FIG. 11 is a perspective view showing a schematic configuration of the power transmission system according to the first embodiment of the present invention. 12 is a top view of the power transmission system of FIG. FIG. 13 is a cross-sectional view taken along line B-B ′ of FIG. 11. The transmission coil 1 and the reception coil 2 are rectangular coils having a square outer periphery of 30 mm × 30 mm, have a wiring width of 0.4 mm, a wiring pitch of 0.4 mm, and a wiring thickness of 0.2 mm, and the number of turns is 5. Times. The transmission coil 1 and the reception coil 2 face each other with a distance d = 2 mm. A ferrite magnetic body 3 having a thickness of 2 mm and a relative permeability of 10 is provided between the transmission coil 1 and the reception coil 2. FIG. 14 is a circuit diagram showing an equivalent circuit of the power transmission system of FIG. Q1 is a signal source, Z1 is a load impedance, and C3 and C4 are capacitors loaded for matching. Capacitors C3 and C4 have a capacity of 20 nF. FIG. 15 is a diagram for explaining a positional shift generated between the transmission coil 1 and the reception coil 2 in the power transmission system of FIG. 11. The receiving coil 2 was displaced in the Y direction with respect to the transmitting coil 1 as shown in FIG. The magnetic body 3 is assumed to have a sufficient length in the Y direction so that the displacement shown in FIG. 15 is possible.

In the computer simulation (FIGS. 16 to 21, 23, and 24), an impedance matrix between the transmission coil 1 and the reception coil 2 is calculated using a finite element method, and transmission between the transmission coil 1 and the reception coil 2 is performed. As the efficiency, 100 × | S21 | ² was obtained.

  FIG. 16 is a graph showing frequency characteristics of transmission efficiency when the positional deviation of the transmission coil 1 and the reception coil 2 is changed in the power transmission system of FIG. 11 from which the magnetic body 3 is removed. FIG. 17 is a graph showing frequency characteristics of transmission efficiency when the positional deviation between the transmission coil 1 and the reception coil 2 is changed in the power transmission system of FIG. When there is no magnetic body 3 (FIG. 16), it can be seen that as the displacement between the transmission coil 1 and the reception coil 2 increases, the resonance frequency shifts to a higher frequency band and the transmission efficiency decreases. Assuming that the operating frequency is about 700 kHz, a large variation in transmission efficiency occurs. This is because the magnetic flux penetrating between the transmission coil 1 and the reception coil 2 decreases and the mutual inductance M decreases due to a shift in the positions of the transmission coil 1 and the reception coil 2. On the other hand, in the power transmission system including the magnetic body 3 of the present embodiment (FIG. 17), it can be seen that the fluctuation in transmission efficiency is suppressed to a small extent due to the effect of widening the bandwidth. That is, it can be seen that the power transmission system of the present embodiment has a special effect of being resistant to misalignment.

  FIG. 18 is a graph showing the characteristics of transmission efficiency with respect to the positional deviation of the power transmission system of FIG. The configuration of the power transmission system is the same as that shown in FIGS. 11 to 14, and the operating frequency is 680 kHz. For example, when a range in which the transmission efficiency is 60% or more is obtained, the comparative example (without magnetic material) allows a deviation of up to 5 mm, and the example can allow a positional deviation of up to 13 mm. It can be seen that the power transmission system of the present embodiment has a strong tolerance against the positional deviation of the transmission coil 1 and the reception coil 2.

  The fact that the resistance to displacement is increased means that the relative change in the coupling coefficient is small even if the positions of the transmission coil 1 and the reception coil 2 are displaced.

  Next, characteristics when the relative permeability of the magnetic body 3 is changed in the power transmission system of this embodiment will be described with reference to FIGS. 19 to 21, the configuration of the power transmission system is shown in FIGS. 11 to 14 except for the thickness of the magnetic body 3 (equal to the distance between the transmission coil 1 and the reception coil 2) and the relative permeability. It is the same as that. However, the capacitances of the capacitors C3 and C4 are 10 nF.

FIG. 19 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. In the case of FIG. 19, the thickness of the magnetic body 3 is 2 mm. According to FIG. 19, when the relative permeability μ _r = 2 shows a bimodal characteristic, when the relative permeability μ _r = 7, the bandwidth is increased while maintaining the transmission efficiency, and the relative permeability μ _r = 20. As a result, the transmission efficiency is reduced. Therefore, it can be confirmed that an optimal relative permeability μ _r exists. FIG. 20 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. 11 in which the thickness of the magnetic body 3 is reduced. For Figure 20, the thickness of the magnetic body 3 is 1 mm, relative permeability mu _r was used the same value as in Figure 19 for comparison. By reducing the thickness of the magnetic body 3, the coupling coefficient k between the transmission coil 1 and the reception coil 2 increases. In the case of FIG. 19, optimum characteristics were obtained when the relative magnetic permeability μ _r = 7, but this does not hold when the thickness of the magnetic body 3 is changed. FIG. 21 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. 11 in which the thickness of the magnetic body 3 is reduced. Even in the case of FIG. 21, the thickness of the magnetic body 3 is 1 mm, but a relative magnetic permeability different from those in FIGS. 19 and 20 was used. According to FIG. 21, when the thickness of the magnetic body 3 is decreased, a broadband having the same relative permeability as that before the thickness is decreased by using a magnetic body having a large relative magnetic permeability (for example, μ _r = 14). It can be seen that the operation can be realized. As described above, the power transmission system according to the present embodiment has a special effect that it can cope with a reduction in thickness by increasing the relative permeability. Reducing the thickness of the magnetic body 3 leads to cost and weight reduction.

  Next, with reference to FIG. 22 to FIG. 24, characteristics when the cavity is provided in the magnetic body 3 in the power transmission system of the present embodiment will be described.

  FIG. 22 is a top view showing a schematic configuration of the power transmission system according to the second embodiment of the present invention. The power transmission system of FIG. 22 has the same configuration as the power transmission system shown in FIGS. 11 to 14 except that a cavity is provided in the magnetic body 3. The dimension of the cavity is 14 × 14 mm. FIG. 23 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. 22 from which the cavity is removed. FIG. 24 is a graph showing frequency characteristics of transmission efficiency when the relative permeability of the magnetic body 3 is changed in the power transmission system of FIG. Comparing the graphs of FIGS. 23 and 24, it can be seen that substantially similar characteristics can be obtained regardless of the presence or absence of cavities. In the power transmission system of the present embodiment, the magnetic body 3 only needs to be provided in the vicinity of the transmission coil 1 and the reception coil 2 at least over the region where the windings of the transmission coil 1 and the reception coil 2 exist. Providing a cavity in the magnetic body 3 leads to cost and weight reduction.

  Next, with reference to FIGS. 25 to 27, a further example of the power transmission system of the present embodiment will be described.

  FIG. 25 is a cross-sectional view showing a schematic configuration of a power transmission system according to the third embodiment of the present invention. FIG. 26 is a plan view showing the transmission coil 1 and the reception coil 2 of FIG. Below the transmission coil 1, a magnetic body 11 and a metal shield 12 are provided for shielding, and above the reception coil 2, a magnetic body 13 and a metal shield 14 are also provided for shielding. The thicknesses of the magnetic bodies 11 and 13 and the metal shields 12 and 14 are 0.1 mm. The shield has the effect of reducing leakage electromagnetic fields and reducing the influence on peripheral devices. The relative permeability of the magnetic body 3 is 10, and the relative permeability of the magnetic bodies 11 and 13 is 1000. As shown in FIG. 26, the transmission coil 1 and the reception coil 2 are circular coils having an outer diameter of 29 mm, an inner diameter of 12.5 mm, and 17 turns. The windings of the transmission coil 1 and the reception coil 2 have a width of 0.48 mm and a thickness of 0.3 mm, and each of the transmission coil 1 and the reception coil 2 has an inductance of 11.7 μH and a series resistance of 0.4Ω.

  FIG. 27 is a graph showing frequency characteristics of transmission efficiency of the power transmission system of FIG. The graph of FIG. 27 shows the results obtained by actual measurement. The distance d between the transmission coil 1 and the reception coil 2 is 2.6 mm, and the case with a magnetic body (solid line) is compared with the distance d = 2.6 mm and no magnetic body. A simulation was performed in the case of (dotted line) and the case where the distance d = 7.5 mm and no magnetic substance (dotted line). The thickness of the magnetic body 3 is assumed to be equal to the distance d. In the case of “no magnetic material, d = 2.6 mm”, the transmission coil 1 and the reception coil 2 are close to each other and electromagnetically strongly coupled, so that the transmission efficiency is maximized at a frequency of 150 kHz. Operation has not been realized. In the case of “no magnetic material, d = 7.5 mm”, the transmission coil 1 and the reception coil 2 are separated from each other, so that the mutual inductance is lowered, and thus the coupling coefficient can be lowered. As a result, wideband operation can be realized. However, at that time, the frequency at which the transmission efficiency is maximized increases to 250 kHz. That is, the power transmission system is substantially enlarged. On the other hand, in the case of “there is a magnetic material and d = 2.6 mm”, that is, the frequency characteristic of the transmission efficiency of the power transmission system according to the embodiment is maximized at 150 kHz, and the bandwidth of the transmission efficiency (for example, the transmission efficiency is 60 It can be seen that the bandwidth is also wider than the case of “no magnetic material, d = 2.6 mm”. In addition, the frequency at which the transmission efficiency is maximized is lower than in the case of “no magnetic material, d = 7.5 mm”. From the above results, the power transmission system of the present embodiment has a special effect that it is possible to simultaneously realize a wide band and a small size.

  Several applications of the present invention are described below.

  FIG. 28 is a block diagram showing a schematic configuration of the power transmission system according to the first embodiment of the present invention. A power transmission system including the non-contact connector system described above can be configured. The power transmission system includes a power transmission device on the power transmission side provided with the non-contact connector device on the transmission side and a power transmission device on the power reception side provided with the non-contact connector device on the reception side. Referring to FIG. 28, in the power transmission device on the power transmission side, the transmission coil 1 (FIG. 1) is connected to the power transmission circuit 102, and the power transmission circuit 102 is connected to the power source 101. In the power transmission device on the power receiving side, the receiving coil 2 (FIG. 1) is connected to the power receiving circuit 103, and the power receiving circuit 103 is connected to a load 104 (for example, a battery). When power is supplied to the transmission coil 1, a current flows through the transmission coil 1, an induced electromotive force is generated in the reception coil 2 due to an electromagnetic field around the transmission coil 1 formed by the current, and an induced current is generated in the reception coil 2. Flowing. By extracting this induced current with the load 104, power can be transmitted between the transmission coil 1 and the reception coil 2.

  FIG. 29 is a cross-sectional view illustrating the configuration of the power transmission device on the power transmission side and the power transmission device on the power reception side in the power transmission system of FIG. 25. When the power transmission system of the present embodiment is implemented (for example, wireless charging), the transmitter 4 and the magnetic body 3 are provided inside the housing 4 of the power transmission device (charger) on the power transmission side, and the power on the power reception side. It is desirable to provide only the receiving coil 2 inside the housing 5 of the transmission device (device to be charged). The receiving coil 2 faces the surface (first surface) of the magnetic body 3 on the side where the transmitting coil 1 is provided (first surface) when the power transmitting device on the power receiving side is brought close to the power transmitting device on the power transmitting side ( A winding is provided around a predetermined area on the second surface). When power transmission is not performed, the reception coil 2 is separated from the transmission coil 1 and the magnetic body 3. When power transmission is performed by bringing the power transmission device on the power receiving side close to the power transmission device on the power transmission side, the receiving coil 2 is close to the magnetic body 3 over at least the region where the winding of the receiving coil 2 exists, and the receiving coil 2 Is made close to the magnetic body 3 to increase the self-inductance of the receiving coil 2. Thereafter, the operation is the same as described with reference to FIG.

  FIG. 30 is a cross-sectional view illustrating a configuration of a modification of the power transmission device on the power transmission side and the power transmission device on the power reception side in the power transmission system of FIG. 25. The magnetic body may be provided in both the power transmission device on the power transmission side and the power transmission device on the power reception side. In the power transmission system of FIG. 30, the transmission coil 1 and the magnetic body 3a are provided inside the casing 4 of the power transmission apparatus on the power transmission side, and the magnetic body 3b and the magnetic body 3a are disposed inside the casing 5 of the power transmission apparatus on the power reception side. Only the receiving coil 2 is provided. When power transmission is not performed, the reception coil 2 is separated from the transmission coil 1. When the power transmission device on the power reception side is brought close to the power transmission device on the power transmission side to perform power transmission, the reception coil 2 is electromagnetically coupled to the transmission coil 1. By increasing the respective self-inductances of the transmission coil 1 and the reception coil 2 by the magnetic bodies 3a and 3b, the coupling coefficient between the transmission coil 1 and the reception coil 2 can be increased in the transmission efficiency from the transmission coil 1 to the reception coil 2. The frequency characteristic can be set to be lowered so as to change from a bimodal and narrow band characteristic to a unimodal and wide band characteristic. Thereafter, the operation is the same as described with reference to FIG.

  29 and 30, the casings 4 and 5 are made of, for example, a dielectric such as ABS resin or rubber, an insulator, or both. Note that at least one of the casings 4 and 5 can be made of a magnetic material. For example, the relative magnetic permeability of the housing can be increased by mixing magnetic powder into the housing (dielectric). Furthermore, it is possible to integrate the magnetic body 3 with the casing 4 or 5 made of a magnetic material. By integrating the magnetic body 3 and the housing 4 or 5, there is an effect that the power transmission system can be reduced in thickness, and the number of members is reduced, so that reduction in cost and weight can be expected.

  According to the power transmission system of the present embodiment, power can be transmitted with stable transmission efficiency even if a positional shift occurs between the transmission coil 1 and the reception coil 2 even though the configuration is very simple.

Second embodiment.
FIG. 31 is a block diagram showing a schematic configuration of a signal transmission system according to the second embodiment of the present invention. Instead of transmitting power using the non-contact connector system described above, a signal may be transmitted. The signal transmission system includes a transmission-side information transmission device including a transmission-side non-contact connector device and a reception-side information transmission device including a reception-side non-contact connector device. Referring to FIG. 31, in the information transmission apparatus on the transmission side, the transmission coil 1 (FIG. 1) is connected to the transmission circuit 112, and the transmission circuit 112 is connected to the signal source 111. In the information transmission apparatus on the reception side, the reception coil 2 (FIG. 1) is connected to the reception circuit 113. The information transmission device on the transmission side and the information transmission device on the reception side in the signal transmission system can be configured similarly to the power transmission device on the power transmission side and the power transmission device on the power reception side shown in FIG. According to the information transmission system of the present embodiment, information can be transmitted with stable transmission efficiency even if a positional shift occurs between the transmission coil 1 and the reception coil 2 even though the configuration is very simple.

Third embodiment.
FIG. 32 is a block diagram showing a schematic configuration of an induction heating apparatus according to the third embodiment of the present invention. FIG. 33 is a cross-sectional view showing the configuration of the induction heating device and pan 123 of FIG. The induction heating apparatus can be configured using the principle of the power transmission system described above.

  Referring to FIG. 32, in the induction heating apparatus, transmission coil 1 (FIG. 1) as an induction heating coil is connected to cooking circuit 122, and cooking circuit 122 is connected to power supply 121. Furthermore, instead of the receiving coil 2 of FIG. 1, an induction heating cooking container such as a pan 123 is provided. The pan 123 is provided close to the transmission coil 1 so as to be electromagnetically coupled to the transmission coil 1. When a current flows through the transmission coil 1 due to electromagnetic coupling between the transmission coil 1 and the pan 123, an induced electromotive force is generated on the bottom surface of the pan 123 by an electromagnetic field around the transmission coil 1 formed by the current. As a result, the induced eddy current flows to the bottom surface of the pan 123. Since this eddy current can be regarded as an equivalent lossy coil, the self-inductance of the pan 123 and the mutual inductance between the transmission coil 1 and the pan 123 can be defined. The transmission coil 1 is provided along the first surface so as to wind a winding around a predetermined region on the horizontal first surface. The induction heating device includes at least the winding of the transmission coil 1 and the pan 123 between the first surface and the second surface that is close to and opposes the upper side of the first surface and the bottom surface of the pan 123 is located. The magnetic body 3 provided in close proximity so as to be electromagnetically coupled to the bottom surface of the transmission coil 1 and the pan 123 over the region where the bottom surface exists. The self-inductance of the transmission coil 1 is increased by bringing the magnetic body 3 close to the transmission coil 1, and the self-inductance of the pot 123 is increased by bringing the magnetic body 3 close to the bottom surface of the pan 123.

  According to the induction heating device of the present embodiment, by increasing the respective self-inductances of the transmission coil 1 and the pan 123, the coupling coefficient between the transmission coil 1 and the pan 123 is transmitted from the transmission coil 1 to the pan 123. The frequency characteristic of efficiency is set to be lowered so that the characteristic changes from a bimodal and narrow band characteristic to a unimodal and broadband characteristic. According to the induction heating device of the present embodiment, the pan 123 can be heated with a stable transmission efficiency even if a positional shift occurs between the transmission coil 1 and the pan 123, although the configuration is very simple.

Modified example.
Hereinafter, a modification of the embodiment of the present invention will be described with reference to FIGS. 34 to 36. In the embodiment and examples described with reference to FIG. 1 and others, the winding of the transmitting coil 1 is wound in a single layer along the first surface, and the winding of the receiving coil 2 is along the second surface. However, the winding may be wound in multiple layers.

  FIG. 34 is a cross-sectional view showing a modification of the transmission coil 1 and the reception coil 2 of FIG. FIG. 35 is a schematic diagram for explaining how to wind the transmission coil 1 of FIG. 34 and 35 show a case where each of the transmission coil 1 and the reception coil 2 is wound in two layers. The windings 1a and 1b of each layer of the transmission coil 1 are wound in opposite directions, and are connected by terminals Pb and Pd, whereby the windings 1a and 1b are connected in series with each other. By connecting the windings 1a and 1b in series, the inductance of the transmission coil 1 can be increased. The same applies to the receiving coil 2.

  FIG. 36 is a schematic diagram for explaining a modification of the winding method of the transmission coil 1 of FIG. The windings 1a and 1b of each layer of the transmission coil 1 are wound in the same direction, connected by terminals Pa and Pc, and further connected by terminals Pb and Pd, whereby the windings 1a and 1b are connected in parallel to each other. The By connecting the windings 1a and 1b in parallel, the resistance of the transmission coil 2 can be reduced.

  The total length of each of the transmission coil 1 and the reception coil 2 needs to be significantly shortened with respect to the operating wavelength.

  At least one of the transmission coil 1 and the reception coil 2 may be wound in multiple layers. Moreover, each or at least one of the transmission coil 1 and the reception coil 2 may be wound in three or more layers.

  FIG. 37 is a cross-sectional view showing a modification of the non-contact connector device on the transmission side and the reception side of FIG. The non-contact connector device may be formed on a printed wiring board. In this case, the transmission coil 1 and the reception coil 2 are formed as conductor patterns on the dielectric substrates 7 and 8, respectively. A magnetic body 3a is applied on the transmission coil 1 and the dielectric substrate 7, and a magnetic body 3b is applied on the reception coil 2 and the dielectric substrate 8 (the lower surface of the dielectric substrate 8 in FIG. 37). Thus, by forming the transmission coil 1 and the reception coil 2 on the printed circuit board integrally with the magnetic bodies 3a and 3b, a non-contact connector device with high strength and low cost can be provided. Further, in at least one of the non-contact connector device on the transmission side and the reception side, the transmission coil 1 or the reception coil 2 on the printed wiring board may be formed integrally with the magnetic body.

  Further, the capacitors loaded on the transmission coil 1 and the reception coil 2 for matching are connected in parallel to the transmission coil 1 and the reception coil 2 in FIG. 14, but are connected in series as shown in FIG. May be. Other matching circuits may be used.

  Here, the operating principle of the present invention will be supplemented. Considering the case where radio waves are radiated from the transmitting antenna to the receiving antenna in contrast to the present invention, the transmitting antenna and the receiving antenna are separated from each other and are in an electromagnetically uncoupled state. Even if it changes, the bandwidth does not change. However, in the non-contact connector system, since the transmission coil and the reception coil are close to each other and are electrically coupled, the bandwidth varies depending on the coupling state. Therefore, if the narrow band is designed, the frequency at which the transmission efficiency is maximized is shifted only by a slight change in the distance between the transmission coil and the reception coil, resulting in a decrease in transmission efficiency. In the non-contact connector system described in the embodiment of the present invention, a wide band operation is realized by providing the magnetic body 3 between the transmission coil 1 and the reception coil 2, and as a result, the transmission efficiency is maximized by a slight positional deviation. Even if the frequency to be changed changes (see FIG. 17), fluctuations in transmission efficiency can be suppressed. As described above, by realizing a wide band operation, even when a positional deviation occurs between the transmission coil 1 and the reception coil 2, transmission efficiency can be maintained at a desired frequency.

  Some conventional techniques provide a magnetic body between a transmission coil and a reception coil. For example, the invention disclosed in Patent Document 1 is known. However, since the invention of Patent Document 1 uses a magnetic body to increase the coupling coefficient between the transmission coil and the reception coil, as in FIG. 8 of the present application, the purpose of using the magnetic body in the present invention, That is, it is completely different from the use for increasing the respective self-inductances of the transmission coil 1 and the reception coil 2 to decrease the coupling coefficient. The magnetic material used in the invention of Patent Document 1 has a high relative magnetic permeability in order to increase the coupling coefficient. On the other hand, the magnetic material used in the present invention can have a relatively small relative permeability.

  According to the non-contact connector device, the non-contact connector system, the power transmission device, and the power transmission system of the present invention, even if a positional deviation occurs between the transmission coil and the reception coil, it is stable even though the configuration is very simple. Electric power can be transmitted with transmission efficiency.

  According to the information transmission apparatus and the information transmission system of the present invention, it is possible to transmit information with a stable transmission efficiency even if a positional deviation occurs between the transmission coil and the reception coil even though the configuration is very simple. .

  According to the induction heating device of the present invention, the cooking container can be heated with a stable transmission efficiency even if a positional shift occurs between the induction heating coil and the cooking container, although the configuration is very simple.

1, 1a, 1b ... transmitting coil,
2, 2a, 2b ... receiving coil,
3, 3a, 3b, 6, 11, 13 ... magnetic body,
4, 5 ... housing,
7, 8 ... dielectric substrate,
12,14 ... Metal shield,
101 ... Power supply,
102 ... power transmission circuit,
103: Power receiving circuit,
104 ... load,
111 ... Signal source,
112 ... transmission circuit,
113 ... receiving circuit,
121 ... Power supply,
122 ... Cooking circuit,
123 ... pot,
C1 to C4 capacity
L1, L2 ... Self-inductance,
M ... Mutual inductance,
P1a, P1b, P2a, P2b, Pa, Pb, Pc, Pd ... terminals,
R1, R2 ... resistance,
Q, Q1 ... signal source,
z01, z02, Z1... load impedance.

Claims (6)

In an induction heating apparatus provided with an induction heating coil provided in close proximity so as to be electromagnetically coupled to a cooking vessel,
The induction heating coil winding is wound on a horizontal first surface;
The induction heating device is
At least the winding of the induction heating coil and the cooking vessel between the first surface and a second surface that is close to and opposes the upper side of the first surface and on which the bottom surface of the cooking vessel is located A magnetic body provided in proximity to the induction heating coil and the bottom surface of the cooking vessel over a region where the bottom surface of
The self-inductance of the induction heating coil is increased by bringing the magnetic body close to the induction heating coil, and the self-inductance of the cooking container is increased by bringing the bottom surface of the cooking container close to the magnetic body. Induction heating device.   By increasing the respective self-inductances of the induction heating coil and the cooking vessel, the coupling coefficient between the induction heating coil and the cooking vessel can be determined by the frequency characteristic of the transmission efficiency from the induction heating coil to the cooking vessel. 2. The induction heating apparatus according to claim 1, wherein the induction heating device is set to be lowered so as to change from a bimodal and narrow band characteristic to a single peak and broadband characteristic.   The induction heating apparatus according to claim 1 or 2, wherein the winding of the induction heating coil is wound in a single layer along the first surface.   The winding of the induction heating coil is wound in multiple layers along the first surface, and the windings of each layer of the multilayer windings are connected in series with each other. 2. The induction heating apparatus according to 2.   The winding of the induction heating coil is wound in multiple layers along the first surface, and the windings of each layer of the multilayer windings are connected in parallel to each other. 2. The induction heating apparatus according to 2. The winding of the induction heating coil is formed as a conductor pattern on the dielectric substrate along the first surface,
The induction heating apparatus according to claim 1 or 2, wherein the magnetic body is formed integrally with the induction heating coil and the dielectric substrate.

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